Automatic two-blade shutter for cameras



I c. c. FUERST AUTOMATIC TWO-BLADE SHUTTER FOR CAMERAS July 12, 1949.

Filed Nov. 26, 1946 -C'ARL C. FUERST INVESTOR BY a a HTTORNEYS PatentedJuly 12, 1949 UNITED STATES PAT QFFICE 2,475,952 AUTOMATiC Two-BLADEsnirrnia role CAMERAS can o. Euerst, Rochester, N. 11;, assigns! to" manKodak compan Rochester, N. Y., a 661" aeration of New Jersey ApplicationNovember 26, 1946, Serial N6. (01. 95-62) This invention relates tophotography and particularly to a simple type of camera shutter. Oneobject of my invention is to provide an inexpensive camera shutterconsisting of comparatively-few, relatively-simple parts. Another objectof my invention is to provide a shutter which can be readily assembledby relatively-unskilled help. A still further object is to provide ashutter Which is reliable and which will produce a short range ofexposures and maintain these exposures. A still further object of myinvention is to provide a shutter in which the parts do not have to bemade with extreme accuracy to produce the desired results. Other objectswill appear from the following specification, the novel features beingparticularly pointed out in: the claims at the end thereof.

Coming now to the drawings wherein like reference characters denote likeparts throughout:

Fig. l is a front plan View of a. shutter with the shutter cover removedconstructed in accordance with and embodying a preferred form of myinvention;

Fig. 2 is a fragmentary sectional view taken on line 2'-2 of Fig. 1,certain parts being incompletely shown; i

Fig. 3 is an enlarged fragmentary detail partially section taken on line3+3 of" Fig. 1;.

Fig. 4 is an enlarged fragmentary part section taken on line 4-4" ofFig;1;

Fig. 5 is a View similar to Fig. 4 but with the parts in a differentposition;

Fig. 6 is a fragmentary detail enlarged view partially in Section and"taken on line 6-5 of Fig. 1-;

Fig. 7 is a View similar to Fig. 6 but with the parts in a differentposition;

Fig. 8' is an enlarged fragmentary sectionalview through one of theresilient master member holding clips; and

Fig. 9 is a fragmentary detail illustrating a retarding mechanism whichcan he used with the shutter shown in Fig.- 1 if slow, instantaneousexposures" are desired.

My present inventionmay be considered to be many simplifications: havebeen made, although the shutter cloes include the same: typeof tw ceblade construction As indicated in- Fig".- 1 Shiltliel may consist of acasing I having an; upstanding flange 2 aroundthe perip ery antiexposure opening 3 in the center of the; casing. The flange 2 is slotted(so-that a shatter trigger 5 may project through thefiange and ma move:from the full iine rest ennies in Fig. 1 to the" broken line position ofthe same figure. The trigger 5" is pivotegi on a stud 6" and a; sprin Tnormally holds the triggerin its rest pesln ii, shown, A stop pin 8" onthe mechamsm piate 9 may limit the movement of the trigger in onedirection.

The-trigger is edapteete cedperate with a bent finger In which may beformed from the metal or the ring-shaped master member l'l, this mastermemb'hturnifig' ab an upwardly-extending flange 12 on the" mechanismstate 91 A spring l3, attached to a pin I 4', carried by the master member and to" a stud I 5 earned Hy the mechanism plate 9', normally Holds"the master member in its rest position; shown n Fig. 1 with one edge H;of a cut-out portion If? at rest against a stop" pin [8. The master mster may oscillate through a range not reater than the distance betweenthe shoulders t6 and" [9". n, v,

The downwardlyrained" finger to; as best shown in Fig 4- and 6', pese'rit's a straight edge 28th the end 21; of the tri g'ger 5 in onedirectionthat is in the direction engaged by the trigge end 2| Whenitlsbe ng indve rr m its rest position to the dotted Ddsifld ir'iFig'. 1.Thus, dl'lfifig this mevemnt the n get" is engaged and the master memberis moved td seaside the spring ['3' up to the time thaliith el'i d I?"(if the fii-gger' slips off The sense is" their free to turn the mastermemberin a; reverse direenon to open and. close the shutter blades, aswill be hereinafter more fully des "ed t 7 As shown the finger Hl'isalso provided witha beveledi or tapered'l surface 23 which may beengaged loytfie end 21 df'itfie trigger When-it moves underthe'influence 0t spring: I to itsrest position.- Because of this beveledsurface, it lifts the finger 10' and with it the master member I I, sothat it may pass freely under this springv finger. This movement ispermitted because ofa pair of oppositely-disposed spring clips 2-4 and24a, clip a'; plane" apes the mechanism plate 9, nevert ele they"permitso that the master member may rock from its plane when the triggerpasses under the bent-over finger 10. It may also do the same thing whenthe blade pin 21, which also has a beveled surface 28, passes under ablade operating cam 29 preferably integrally formed on he master memberI l.

The blade-operating cam 29 presents one flat surface 30 to the beveledside '28 of the bladeoperating pin 21 so that in moving towards itsspring tension position the blade ring H may rock more or less axiallyfrom its normal plane of movement so as to snap over the pin 21. Whenring ll moves in an exposure-making direction there is a cam surface 31which strikes the straight side 32 of the blade-operating pin 21 so thatthe blade ring swings pin 21 outwardly and past cam 58 until the cam 58passes pin 27 allowing the shutter blades to close.

The blade ring pin 21 is carried by one of the two shutter blades 35 andpasses through an elongated opening, or slot 36, in the other shut terblade 31. A spring 38 coiled about a shoulder 39 on the pin normallyholds the pin in the psition shown in Fig. 1 in which the shutter bladesare held closed. Blade 35 is pivoted upon a pin :30 and blade 31 ispivoted upona pin 4|, the pins 48 and 4| retaining the ends 42 and 43 ofthe spring 38 in an operative position.

The shutter blades 35 and 3'! are very much alike, being substantiallythe same shape except that one is a right-hand and theother is alefthand blade. In the normal position of rest, they overlap and coverthe exposure opening 3. However, when the pin 27 is struck by therapidlymoving master member II, the cam surface 3! moves the pin 21towards the flange 2 simultaneously opening both blades, and after thecam 29 has passed, permitting the blades to close rapidly when the pin21 snaps down past the shoulder as.

If a single speed shutterlis required with an exposure which isrelatively fastsay A of a second-the mechanism may not require a retard.However, it is a comparatively simple matter to obtain a shutter withand of a secend, as well as bulb exposures, so that where this isrequired, the gear retard, shown in Fig. 9, may be employed. If the gearretard is used, the master member I I may be provided with a retard pin50 adapted to lie in the path of an edge 5! of a gear sector 52, thegear teeth of which, 53, mesh with the pinion 54 having ratchet teeth Apallet 56 may engage this ratchet. A pin 51 may be moved by a suitablecam to engage the cam surface 5| more or less with the pin 5!] todetermine the length or duration of the short, instantaneous exposures.The pin 58 is positioned on the master member ll so as to strike the camsurface 5| while the blade pin 2! is riding on the flat surface 58 onthe end of the cam 29. Consequently, the retarding action takes placewhile the blades are fully opened and the pin 50 rides past the end ofthe sector 52 when the blade ring pin 21 reaches the shoulder 38.

The shutter above described consists of extremely few parts, practicallyall of which can be stamped from sheet metal with a minimum number offorming operations. The construction is such that the parts go togetherreadilyand can be assembled with relatively-unskilled help and there arevery few extremely close tolerances which require hand work or fittingin assembling the shutter.

The operation of the shutter is extremely simple. By depressing thetrigger 5, the trigger end 2| engages the finger ID on the straight side29 moving the master member ll until the spring I3 is tensioned, Duringthis movement the bladeoperating cam 29, through its straight edge 38,engages the blade ring pin 21 and since the spring clips 24 and 24a willfreely flex, the blade ring H moves from its normal plane of movement ashort distance axially in riding up and over the pin 21, the blade ringI I returning to its normal plane of movement just before the end 2! ofthe trigger rides off the bent finger Hi. When the trigger releases themaster member, the spring I3 rapidly turns the master member in acounter" clockwise direction so that the cam 29, through its inclinededge 3|, engages the straight side 32 of the pin 21 and rapidly opensthe shutter blades 35 and 31. The blades are held open while the pinrides over the surface 58 of the cam 29 and the spring 38 rapidly closesthe blades when the pin 21 snaps back to its Fig. 1 position.

This movement occurs quite rapidly and I have found that an actual /1 ofa second can readily be obtained without too great a force being appliedto the trigger 5. Higher speeds are possible but they usually impose anundesirable trigger load which is sometimes apt to shake the shutter inmaking an exposure. If the gear retard shown in Fig. 9 is employed, aslower exposure can be obtained by moving an adjusting cam to throv. thegear segment 52 into the path of the pin thus slowing up the movement ofthe master member during the time the pin 2'3 is riding on the surface58 of the cam '29.

I claim:

1. A shutter for photographic cameras comprising, in combination ashutter casing having an exposure opening therein, a pair of shutterblades oscillatably mounted on pivots therein, an operating pin on oneblade extending through a slot in the other blade for movingtransversely of the pivots to oscillate the blades by moving radially ofthe shutter, a beveled surface on the pin, a master member extendingaround the exposure opening to oscillate on the shutter casing, a bladepin operating cam thereon having a path of movement intercepting theoperating pin, a pivotally-mounted trigger spring-held in a restposition on the shutter at substantially 189 from the operating pin andmovable through a path, pair of spring clips holding the master memberresiliently against the casing, said spring clips being oppositelydisposed and substantially midway between the trigger and theblade-operating pin whereby said master member may move axially as wellas oscillate about the axis of the casing, a beveled finger on one sideof the master member lying in the path of movement of the trigger, thebeveled surface on the operating pin moving the master member axiallyduring the first part of the trigger movement to set and release themaster member and the beveled surface on the master member moving themaster member axially when the trigger returns to its normal position ofrest.

2. A shutter for photographic cameras as defined in claim 1characterized by a retard pin carried by the master member, a retardinggear train including a gear segment having a cam surface thereon carriedby the casing and means for moving the cam surface to and from the pathof the retard pin carried by the master member for controlling the speedof an exposure, said retard pin being of a height to engage the gearsegment in all positions of the master member.

3. A shutter for photographic cameras comprising, in combination ashutter casing having an exposure opening therein, a pair of shutterblades osoillatably mounted on pivots therein, an operating pin on oneblade extending through a slot in the other blade for movingtransversely of the pivots to oscillate the blades and having a path ofmovement, a beveled surface on the pin, a master member extending aroundthe exposure opening, a mount for the master member on which the mastermember may lie in a plane, said mount including a pair ofoppositely-disposed spring clips under which the master member mayoscillate in a plane and rock from said plane, a blade pin operating camcarried by the master member in position to coact with the blade ringpin, a trigger lug carried by the master member opposite to the bladepin operating cam, said spring clips lying substantially midwaytherebetween, the beveled surface of the operating pin rocking themaster member from its normal plane when passing beenath the blade ringoperating cam during movement of the master member by the trigger, atrigger spring-held in a rest position and having an operating fingerbeveled on one side positioned to coact with the trigger lug carried bythe master member and for moving the master member by the trigger lug,said operating finger beveled on one side rocking the master member inan Opposite direction on the shutter casing when said trigger is movedby its spring to a normal rest position, said spring clips flexing ateach movement of the master member from its plane.

CARL C. FUERST.

REFERENCES CITED The following referenlces are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 764,421 Bullard July 5, 19042,326,077 Steiner Aug. 3, 1943

